Scanned probes are widely used for metrology, patterning and manipulation on the nanometer scale. For a number of applications, it is important that only the desired part of a surface or structure be exposed to the interacting probe because the probe may be changed or may change the structure in an undesired fashion. For example, in biological applications, samples can be extremely delicate and interactions with the probe may damage the sample.
Similarly, the absolute positioning of a probe with respect to a large, complicated sample can be challenging. One existing approach is to take large scale images recorded with the probe; however, with such an approach, tip endurance may be problematic. For example, in probe lithography, tip wear is an issue. Here, it is advantageous to minimize the interaction with the probing tip. Ideally, the tip should interact with the sample only in the regions that are supposed to be manipulated. The sample may have too much topography to allow large scale imaging with the probe, for example, when the application requires manipulation of a surface of a micro-electro-mechanical system (MEMS) device.
For absolute positioning, it is desirable to combine the high resolution imaging and/or patterning capability of the probe with an imaging technique for the larger scale, capable of imaging true three-dimensional (3-D) structures, meanwhile leaving the high resolution probe off-contact during imaging. As used herein, 3-D imaging refers to imaging surface topography where the magnitude of the topography in the normal direction (z-direction) is of similar magnitude as the lateral extend of the surface structures of interest. One existing approach includes the combination of a scanned probe device with an optical microscope. However, this approach is tedious, expensive, does not adequately image in 3-D and is restricted to some very specialized applications.
Additionally, existing approaches include atomic force microscopes (AFMs). Traditional AFM is a powerful tool for nano-scale imaging and manipulation, but, in existing approaches, it is limited in multi-scale resolution. Existing approaches include a lack of positional information out of contact, tip dimensional constraints, are time intensive and subject to tip wear and contamination. Furthermore, some existing approaches need an accompanying optical microscope for larger scale positioning.